Preservers
Preservers are the main agents of the Company, specialists in different types of artifacts. They look exactly like normal humans, but small differences give them away to observant individuals. Typically a Preserver uses a credenza, which apparently is a piece of data processing, or analytical, equipment suited to their work. When among mortals, the Preserver can conceal the credenza, if necessary, by "merging" it with a piece of ordinary furniture (as Mendoza does in In The Garden of Iden). The technology behind such tricks is not explained in any detail, if at all.
Read more about this topic: Characters In The Novels Of The Company